85 shadow running problem.... HELP??

[dbranco]

85 shadow the never ending project but it is getting there... I just replaced the fuel pump & relays.. Now I have gas to the carbs the bike starts and idles pretty good but damn it heat up quickly... When I try to give it throttle it dies.. Not even quarter throlle and it dies... Checked & cleaned carbs again perfect no dirt clean as a whistle.. So what I need is the air cut valve how does that work.. When the bike is idling and I take the hose to the carbs that tee off and goes to each one I take my compressor and keep an 15 psi pressure to the carbs the bike work great throlle great then shut off air and same thing a little throttle and it dies down... I took the air cut valve apart and it looks like it works fine as much as I know what is does... Can someone explain that to me???? Please this things just keeps on going and never want to go....

I take off the tee that comes off the valve and it tees to the carbs.. just to clarify I hope...
Could it be the valve ???

Thanks
Daniel

[dbranco]

I forgot to mention I put on stock harley dyna pipes witht he same stock headers... Would that make a big difference? It starts and idles fine, I can even up the rpm's witht he choke lever but as soon as I give it throttle it dies....

[Machinehead]

Hey dbranco, Whew....sounds like you've done plenty to correct this. If you are convinced the fuel delivery is ok, I'd suggest checking/cleaning or even replacing the plugs. Once the (new/cleaned) plugs are reinstalled you'll have to confirm that there's proper fire at the gap. Please update this post once fire is acknowledeged at the plug gap.

[dbranco]

I checked the sparks and it is strong... When I first got the bike it had a bad cdi unit or spark unit.. So I replaced it then bad fuel pump then replaced that so now I have gas it starts and idle great to about 3/8 throttle then boggs down... Tomorrow I was thinking about changing my needle height bring it up one notch to get some more gas in there it seams like it is choking out.... I hate carb work because there are some many variables...

I thought I would not have to change anything on the carb because it ran good before I told.. All I did was take out the stock exhaust (rusted out) and welded some stock Dyna pipe (factory) with baffles of coarse I will be drilling them out at a leter date....

By bypassing the air cut valve that made a great leap toward running better.... I tore down the carbs again and the needle was plugged up again the pilot... Would the new fuel filter and the little pre-filter on the bottom of the carb stop that crap from coming in?

I might have to change my main jet also what do you think I really think it still is starving for gas..... My opionion the pipes still get real hot but nothing like before.. I have heat wrap on them and the heat wrap was getting charded or burnt That's hot......

Thanks
Daniel Branco

[dbranco]

I just put everything back together and now the bike run better not good or great.. Now I am too rich I took out the plugs and the a black sooty like charcoal... How to I lean her out? Is it the pilot jet of the main jet? The needle does not move I was going to move the needle and it is a fixed height..

Right now the main is a 125 and the polit id is a 42 I think...

What should I do now? I think it should be the pilot because 1/4 to about half the bike boggs down but if I hit the thottle nice and slow it will rev up to redline....

I am assuming it needs less gas and getting bogged down. I have adjusted the floats to proper height of .300"

Thanks
Daniel

[Machinehead]

I just put everything back together and now the bike run better not good or great.. Now I am too rich I took out the plugs and the a black sooty like charcoal... How to I lean her out? Is it the pilot jet of the main jet? The needle does not move I was going to move the needle and it is a fixed height..

Right now the main is a 125 and the polit id is a 42 I think...

What should I do now? I think it should be the pilot because 1/4 to about half the bike boggs down but if I hit the thottle nice and slow it will rev up to redline....

I am assuming it needs less gas and getting bogged down. I have adjusted the floats to proper height of .300"

Thanks
Daniel


I have no idea as what to suggest for the running/pilot jets. Brian may the info. If the machine is in a RICH condition you might foul the plugs whilst troubleshooting this....

[dbranco]

The bike is defin. rich the plugs are all black caked on chalk... I went down one on the pilot jet to a 40 instead of a 42 it did not look it made a big difference. I closed off the air/fuel screw and that did not do muich either.. Should I play with the main jet? I am soo lost now I have tried everything I still think I have to coat the fuel tank sometimes I get some crap in the pilot jet, but that would make the bike run lean correct with maybe white plug instead of black one?

I guess I don't know enough about it.. I will be forced to take it a real mechanic which I hate to do for 80 a hour come on.... What else can I do?

[Machinehead]

Hey dbranco, At this point I'm only concerned with fuel to the carbs (and carb operation). Do you have a service manual?

Replacing jets and adjusting float levels are really only fixes that would rectify an adjustment made by someone that fugged it up before the sale.

Question: Is there any backfire OR popping noise heard at the pipes?

[dbranco]

Black smoke comes out of the pipes. And no there is no popping noise at all

[Machinehead]

I'll assume you haven't access to a manual.

What happens when you remove the air filter and run it?

[M@Man]

When dbranco first posted, he mentioned that it died when ever he gave it throttle and it heated up quickly. Lean mixtures burn hotter than a rich or normal mixture, so I thought he was way too lean, but now he's mentioned black smoke and no popping, which would indicate to me he's running too rich now.
My manual doesn't go into any detail about the air cutoff valve. The only thing it says is to have it tested by Honda dealer as special tools are requred. Big help that is.
I'll admit that I know only the basics when it comes to these carburators, so these next questions are for Machinehead (or anyone else who can answer)...
What the hell does that air cutoff valve do in the operation of the carbs?
And could the fact that he bypassed it, have anything to do with his problem?
:headscrat

M@

[dbranco]

What an air cut valve does is that on deacelleration it put more air into the carbs you you don;t get that popping or backfiring noise.. That was told me by the dealer he also said when they jet these bike they reccommend you take the air valve off...

Well for sure now I pull the plug out and it has crap load of carbon built on it so it is saying that I am real rich.. I tried going down one side to a 40 on thep pilot and that seames not to help.. I found some rust in the jet so I will be coating the tank with KREEM tomorrow morning.. But that goes back to if I was not getting enough fuel I wiould be running Lean like in the beggining so maybe the jets were not as clogged as before... Right now it is a guess..
I think after coating the tanks this will help me get bwetter fuel and take one more possibiltiy out of the equation... Like clogged jets.......

How low of a jet should I go if I need it? I talked to a local cycle guy and he said by going to a harley pipe the backpressure are different than the stock pipes!!! Yeah alright I said...

That don't help me much they just want me to dropp the bike off and charge me 250 to get her running...

Thanks

[Machinehead]

What happens when the filter is removed?